The present invention relates to a key switch for a keyboard, and more particularly to such a key switch which is easy to assemble and inexpensive to manufacture and, which produces a click sound when depressed.
Regular key switches for computer keyboards include two types. Namely, the mechanical key switches and membrane key switches. Regular mechanical key switches are commonly comprised of a key base, a key cap with plunger means vertically slidably mounted in the key base, return spring means, which automatically pushes the key cap back to its former position after each operation, triggering spring means, which is welded to the circuit board of the keyboard and forced to trigger a contact at the circuit board and to produce a click sound upon each down stroke of the key cap. The assembly procedure of these mechanical key switches is complicated and the manufacturing cost of these mechanical key switches is high because the coupling and positioning structures of the parts of these mechanical key switches are complicated. Furthermore, when the key cap is moved vertically relative to the key base, noises tend to be produced, and the key cap tends to be jammed in the key base when depressed. In a membrane key switch, a rubber cone is mounted on a membrane circuit within a key base, and a key cap is vertically slidably coupled to the key base and depressed to compress the rubber cone, causing the rubber cone to trigger a contact at the membrane circuit. This structure of membrane key switch is soft in touch and produces little noise when depressed. However, this structure of membrane key switch does not produce a click sound to confirm positive triggering of the contact when depressed.